Higher than top speed thru rotation
Build a tower, just so the whole experiment is off the ground so you dont hit anythingh.
On top of the tower put a rotor. On top of a rotor build a horizontal arm, in my case it was 400 blocks long.
On the end place a couple of atmo thrusters, perpendicular to the arm you built, so they can provide propulsion in the direction the rotor rotates. If you build with conveyor blocks you can use hydrogen. Also place a control station or a cockpit.
Set the rotor torque to 0 and thrusters to full power override.
Woila, now you can achive a speed of 1067 m/s wich is over mach 3 lol.
Have some fun :D